Seven-time NASCAR Cup series champion Jimmie Johnson will lose his career-long primary sponsor at the end of 2018 ending a spell of 17 years with his backer Lowe's.

Johnson is currently in the midst of the most difficult spell of his career, having failed to win in the last 27 races - including exiting the playoffs early in 2017.

The American retail company has sponsored Johnson since 2001, partnering for all of his championships and 83 wins.

Johnson, who is 26th in the Cup standings, has a contract through to 2020 with Hendrick.

"I'll always be grateful to Lowe's for taking a chance on me and believing that I could win," he said.

"I'm not sure where I'd be right now if they hadn't committed to the #48 team.

"It's hard to see them move on, but we've made history together and celebrated so much success on and off the track.

"There's still a lot left to do in 2018. I have more to accomplish in this sport.

"I feel the best I've ever felt physically. I'm motivated. I'm focused on winning races and chasing more championships.

"Someone [a new sponsor] will be a big part of writing that story with us. I'm not going anywhere."

Hendrick is now searching for a new 2019 primary sponsor.

"We are so appreciative of everyone at Lowe's. They have been amazing partners," said team owner Rick Hendrick.

"With seven championships, this programme has delivered far beyond what anyone could have imagined.

"It goes without saying that we will fully support Lowe's and our programme together in 2018 as we pursue another championship.

"The success of the relationship has been unbelievable."

Michael P. McDermott, Lowe's chief customer officer added: "Rick Hendrick and his organisation have been exceptional partners, and we could not have asked for more from Jimmie - a consummate champion and an incredible representative for our brand and his sport.

"The #48 team is a valuable property and has been an integral part of building the Lowe's brand, which makes today's decision difficult as we now look to invest in other strategic initiatives.

"Although we are evolving our strategy, there's no question that being a part of seven championships and many history-making moments has been valuable for Lowe's."